That's not the good part. The good part is that the LED filaments can be extracted from the bulb if you smash it carefully. You end up with mains voltage LED filaments that can by re purposed in all manner of designs. There are sites and videos on the Interweb featuring such. Just don't kill yourself as I'd feel (a bit) guilty.

The good part is that the LED filaments can be extracted from the bulb if you smash it carefully.

Those filament LEDs are Osram Soleriq L 38 parts, and cost about a dollar each. But they're a new product and currently hard to get in small quantities. They're in the Digi-Key and Mouser catalogs as "non-stock".

Like all LEDs, they're DC devices and have a current limitation. You'll need at least a diode and a resistor. As with most LEDs, forward current changes rapidly with voltage; the table on p. 9 indicates that it starts to light up at 82V and will burn out somewhere around 90. So you've got to current limit to 12mA. If you put a 10K 2W or higher resistor and a diode good for 120V in series with one, and apply 120VAC, it should light up.

As standalone LEDs, those things have some limitations. They're not sealed in a transparent plastic case. Most LEDs are. They're intended for operation inside a dry helium atmosphere, helium being about 5X as thermally conductive as air. "Moisture-sensitive product is packed in a dry bag containing desiccant and a humidity card." They have a temperature limitation of 55°C, which is quite low.

If you put one in a glass container with dry air and run it at "dim", it should work.

I think that depends on the quality of the lamp in question. Having recently just replaced nineteen 40W incandescent bulbs in a large chandelier with 4W LED filament replacements (allegedly "35W equivilent lamps"), I can honestly say that the level of illumination is now so intensely great that I CANNOT REASONABLY USE THAT LIGHT FOR IT'S INTENDED PURPOSE!

I'm not joking, the light output looks like a bloody great WWII carbon-arc searchlight was just wheeled into the room - it's insanely bright. I'm talking film set level of illumination!

Unfortunately due to the type of power supply in the lamp base (capacitive voltage dropper) these lamps are not suitable for use with dimmer switches. And they were too expensive to just replace with lower wattage ones, so it looks like I'm stuck with them as they are for now (until I can come up with a reasonable 'hack' to reduce the output).

I am a node of Server, Born of flesh and blood, But enhanced by the power of its web. I have no use for pain or fear. My scripts are a focus of my will. My strength is my knowledge. My weapons are my skills. Information is the blood of my body. I am part of the greater network. I am host to the vast data of server. My flesh is weak, But my connection is eternal, And therefore I am a god.

I think that depends on the quality of the lamp in question. Having recently just replaced nineteen 40W incandescent bulbs in a large chandelier with 4W LED filament replacements (allegedly "35W equivilent lamps"), I can honestly say that the level of illumination is now so intensely great that I CANNOT REASONABLY USE THAT LIGHT FOR IT'S INTENDED PURPOSE!

I'm not joking, the light output looks like a bloody great WWII carbon-arc searchlight was just wheeled into the room - it's insanely bright. I'm talking film set level of illumination!

Unfortunately due to the type of power supply in the lamp base (capacitive voltage dropper) these lamps are not suitable for use with dimmer switches. And they were too expensive to just replace with lower wattage ones, so it looks like I'm stuck with them as they are for now (until I can come up with a reasonable 'hack' to reduce the output).

That is an interesting problem. I guess there is a limited number of wattages for those bulbs... Hacking bulb by bulb seems to me a lengthy endeavour, though. Remind me, are these LED elements connected in parallel? I'm assuming there will be a constant voltage across each element, and each element is an LED array in series resistors - or something like that. If so, simply removing individual elements might work and be simple enough.

PSHmmm! Your mention of arc lamp has led me to an article on the Yablochkov candle - most interesting....

That is an interesting problem. I guess there is a limited number of wattages for those bulbs... Hacking bulb by bulb seems to me a lengthy endeavour, though. Remind me, are these LED elements connected in parallel? I'm assuming there will be a constant voltage across each element, and each element is an LED array in series resistors - or something like that. If so, simply removing individual elements might work and be simple enough.

The wattage available depends a lot on the bulb size and shape, and also the manufacturer. Most "candle" bulbs as used in chandeliers are made in only one or two wattages "2W" intended to replace a 25W incandescent, and "4W" which is to replace a 40W.

Seems the 2W lamps would have been more than sufficient to replace the existing 40W lamps in the chandelier.... (cheaper too)

As to their construction, it seems that each led segment is constructed of a series connected linear array of LEDs on a metal or ceramic backing strip, and each segment has a relatively high forward voltage of around 60 - 70V (depending on the number of LEDs in the series) at around 15mA or so. The wattage of each segment strip is around 1W, and because they are spread out, the individual heat output of each tiny emitter diode is not an issue to dissipate via thermal radiation inside the enclosed bulb.

As far as I can tell, there is no special gas filling inside the glass bulb, seems to be ordinary air.

I might try running a lamp with a single diode and smoothing capacitor in series with the power input, this will supply the lamp with a half-wave rectified voltage that effectively bypasses the internal bridge rectifier, and thus will effectively run the lamp at half the mains input voltage. Excessive flicker may be an issue though, hence the smoothing capacitor may need to be fairly chunky and low ESR.

The correct way to modify the lamp is to replace the capacitor voltage dropper with one of a different rating, but that will require I rear off the metal base cap, which has it's own set of problems.

That is an interesting problem. I guess there is a limited number of wattages for those bulbs... Hacking bulb by bulb seems to me a lengthy endeavour, though. Remind me, are these LED elements connected in parallel? I'm assuming there will be a constant voltage across each element, and each element is an LED array in series resistors - or something like that. If so, simply removing individual elements might work and be simple enough.

The wattage available depends a lot on the bulb size and shape, and also the manufacturer. Most "candle" bulbs as used in chandeliers are made in only one or two wattages "2W" intended to replace a 25W incandescent, and "4W" which is to replace a 40W.

Seems the 2W lamps would have been more than sufficient to replace the existing 40W lamps in the chandelier.... (cheaper too)

As to their construction, it seems that each led segment is constructed of a series connected linear array of LEDs on a metal or ceramic backing strip, and each segment has a relatively high forward voltage of around 60 - 70V (depending on the number of LEDs in the series) at around 15mA or so. The wattage of each segment strip is around 1W, and because they are spread out, the individual heat output of each tiny emitter diode is not an issue to dissipate via thermal radiation inside the enclosed bulb.

As far as I can tell, there is no special gas filling inside the glass bulb, seems to be ordinary air.

I might try running a lamp with a single diode and smoothing capacitor in series with the power input, this will supply the lamp with a half-wave rectified voltage that effectively bypasses the internal bridge rectifier, and thus will effectively run the lamp at half the mains input voltage. Excessive flicker may be an issue though, hence the smoothing capacitor may need to be fairly chunky and low ESR.

The correct way to modify the lamp is to replace the capacitor voltage dropper with one of a different rating, but that will require I rear off the metal base cap, which has it's own set of problems.

A slight sideways threadjack, but still relevant to the topic; I have just spotted the 'antique' style long-filament lightbulbs that have rather recently appeared, in of all places, Poundland. Price £1! There were at least 3 types, including the popular 'squirrel-cage' etc.

Ahh yes, I'm subscribed to Mike's YT channel, saw that many moons ago. Most of my knowledge is from Big Clive who has done extensive teardowns, and personal observations of bulbs I have been playing with. I'm trying to build a long thin linear single ended bulb from scratch - but that is another secret project for now.

A slight sideways threadjack, but still relevant to the topic; I have just spotted the 'antique' style long-filament lightbulbs that have rather recently appeared, in of all places, Poundland. Price £1! There were at least 3 types, including the popular 'squirrel-cage' etc.

That is all... carry on!

HP

Oooh! Methinks I shall be taking a look in Poundland soon! I need a pair of them for a lamp project, hopefully my local store will have them.